This invention relates to the generation of power for air conditioning systems, processing and co-generation, and is characterized by a primary gas turbine that produces shaft power and an exhaust that produces a high temperature liquid state heat transfer media for selective uses including steam activated adsorption chilling, steam-jet refrigeration, and steam generating; and by a secondary steam turbine operated by said steam generation to produce shaft power coupled by clutch means through a gear means that reduces the two turbine shaft speeds to a common power shaft speed driving air conditioning systems including a vapor compression chiller system, a vapor compression refrigeration system, and a co-generation system for electrical power.
It is a general object of this invention to drive an air conditioning system with a reduced size and cost effective hybrid power system. To this end a constant speed gas turbine is combined with a constant speed steam turbine operating on steam generated from the exhaust heat of the gas turbine. Generally, there is disparity in the shaft speeds of these two turbines, gas and steam, it being an object of this invention to cooperatively combine the torque outputs of each so as to unite in a common power output shaft to drive either the air conditioning system or the co-generation system. In practice, the shaft speed of a typical gas turbine is 12,000 to 15,000 revolutions per minute (RPM), whereas a typical steam turbine is approximately 3,000 RPM. It is an object of this invention to reduce the shaft speed of the gas turbine and the steam turbine to a common output power shaft speed.
The primary gas turbine is operated at an optimum shaft speed as required, by a mechanical chiller unit or electrical co-generator. In carrying out this invention, the shaft speeds of the two turbines are individually controlled by means of speed limiting governors. The primary gas turbine operates in the Brayton cycle and is the energy producing prime mover, in that it produces shaft power and exhaust heat that contains energy in the Rankine Cycle range. The Brayton turbine cycle employs a compressor followed by a combustion chamber, and an air engine to produce power. An axial flow gas turbine embodiment of the Brayton cycle is characterized by an axial flow compressor that compresses and heats induction air. The compressed air enters a combustion chamber where the temperature is increased by means of burning fuel, a hydrocarbon and preferably gas, while the pressure remains constant. The resulting high temperature mixture of combusted gases and air then enters a turbine at high velocity to perform the work of producing shaft power. The exhaust temperature of a gas turbine is high-in the range of 1500.degree. F. Accordingly, it is an object of this invention to capture the exhaust heat energy from the gas turbine and convert it into additional shaft power by use of a steam turbine. Both gas and steam turbines are reliable in their operation and are characteristically compact.
A feature of this invention is the initial operation of the primary gas turbine that is directly coupled to the air conditioning system or co-generator system, followed by operation of the secondary steam turbine that relies upon the exhaust heat energy recovery from said gas turbine. A feature of this invention, therefore, is the clutch means that couples the shaft drives from the two turbines. In practice, the clutch coupling the steam turbine to the power shaft is an over-riding clutch, for example, a Sprague-type clutch. Therefore, after the gas turbine reaches operating speed, the steam turbine responds to steam generated from the gas turbine exhaust and reaches the shaft speed to complement the power output by adding torque thereto.
The hybrid power system herein disclosed utilizes shaft power from a gas turbine to operate air conditioning, refrigeration processing and co-generation equipment, and also utilizes exhaust heat to operate air conditioning and refrigeration process equipment. A feature of this invention is that the shaft power of the primary gas turbine is supplemented by shaft power from a secondary steam turbine also operating from said exhaust heat, thereby conserving the energy not used by said air conditioning and refrigeration processing. This conserved energy is then used in the co-generation of electrical power. The shaft power of the two turbines can be employed separately for processing systems and co-generation, or jointly through a common power shaft to operate a processing system or co-generator, as is shown and later described, it being an object to conserve energy by using the remainder thereof to drive a co-generator.
A first utilitarian processing system advantageously combined with the hybrid power system herein disclosed is the subject of my co-pending application Ser. No. 08/427,832 filed Apr. 24, 1995, wherein concentrated absorbent solution in a closed absorption chiller is concentrated by vapor compression from an evaporator followed by liquification by a condenser with heat transfer from the condenser into the evaporator, increasing solution concentration and chilling capacity with an increased coefficient of performance, resulting in an increase in chilling. This chiller provides a refrigerant enhancement and absorbent concentrator unit that increases the efficiency of absorption chillers, in any one of the generally recognized types thereof, by increasing the volume of water refrigerant supplying the evaporator at the chilling coils and simultaneously concentrating the absorbent solution at the heat absorber that removes heat from the system for discharge at a cooling tower or the like. It is the chilling mode of operation with which this chiller is particularly concerned, providing a unit that is compatible with and acceptable to existent air conditioning systems of the type under consideration, in either a cooling mode or heating mode as the case may be, and particularly with double effect absorption chiller systems. The basic principle is the use of heat and produce a strong absorbent solution of lithium-bromide and water, and the distillation therefrom of a water vapor refrigerant that is condensed in an evaporator to thereby chill system water that is usefully circulated. The absorbent solution is weakened in the process and heat removed therefrom and eliminated by means of an absorber that transfers said heat to a cooling tower or the like. An enhancer-concentrator unit is employed in circuit with said absorber to remove heat from the system and is adaptable to single or double effect systems.
A second utilitarian processing system advantageously combined with the hybrid power system disclosed herein is the subject of my U.S. Letters Pat. No. 4,290,273 issued Sep. 22, 1981, entitled PELTIER EFFECT ABSORPTION CHILLER-HEAT PUMP SYSTEM, wherein a chiller and heat pump system employs a steam-jet refrigeration unit associated with a condenser and with an evaporator absorption unit, and associated pump means and valve control means for multi-mode operation including; simultaneous heating and cooling, cooling, heating, and simultaneous high temperature heating and cooling. This chiller provides a heat pump in combination with a Steam-Jet Refrigeration Unit, a Condenser, and an Evaporation-Absorber Unit. These components are associated in a system or apparatus put into operation primarily by the application of heat energy and assisted by the application of solar energy or other available waste heat such as engine exhaust; with circulation pumps and control valves for the general object of providing a multi-purpose Chiller-Heat Pump having selective modes of operation, namely: 1) Simultaneous Low Temperature Heating and Cooling; 2) Cooling; 3) Heating; and 4) Simultaneous High Temperature Heating and Cooling.
Steam-jet refrigeration apparatus as it is employed herein is a fluid pressure apparatus that operates through the application thereto of primary high pressure steam used to energize an ejector that induces a secondary fluid in the form of vapor drawn from an evaporation chamber. The primary motive steam is expanded through a converging-diverging nozzle to velocities in the order of 1200 meters per second (4000 fps.) The corresponding nozzle pressure is very high, and the high velocity steam issuing from the nozzle entrains the water vapor leaving the suction-evaporation chamber, and the two streams merge in a mixing section that converges in the direction of flow. Such an arrangement is diagrammed in the drawings. Warm water return is sprayed into an evaporator chamber and the chilled water is withdrawn therefrom and utilized for space conditioning.
A third utilitarian processing system advantageously combined with the hybrid power system disclosed herein is the subject of my U.S. Letters Pat. No. 4,328,677 issued May 11, 1982, entitled PELTIER FREEZE CONCENTRATION PROCESS for the treatment of dilute solutions and freeze concentrations thereof by means of steam-jet refrigeration and pre-cooling of a feed solution sprayed into an absorber-freezer means in which heat is absorbed from the jet refrigeration and from which ice slurry is charged into a melter-worker means discharging product melt and concentrated by-product. The distillation of alcohol from grains and the like produces dilute liquid solutions that are rich in energy producing materials referred to as Distillers Dried Grains and Solubles or "DDGS", which is the main by-product of alcohol production. As a by-product commodity, it is required that DDGS be produced and sold in a dry state or condition, for example, as bulk feed to be used in animal husbandry. Characteristically, and based, for example, upon corn, DDGS is 99% dry substance, 28-31% raw protein, 12-13% raw fat, 10% raw fibers, 5-6% ash, and 41-43% Nitrogen free extract. For example, in the manufacture of Ethanol, the following feed stock can be used: Wheat, Corn, Rice and Sugar.
Accordingly, this Freeze Concentration Process is not to be limited to the material processed, whether it be the purification of a primary fluid such as sea and/or brackish water, or other inorganic and organic solutions refining concentrations such as DDGS. The process involved herein is the vacuum freezing process in which the freezing is accomplished in a stirred tank crystallizer due to the vaporization of water vapor which, in turn, is absorbed in an adjacent chamber by a concentrated solution of sodium chloride (NaCl) diluted by the water vapor pumped to a compressor where it is concentrated to its original strength by vapor compression apparatus using a closed circuit.
It is a general object of this invention, with respect to said third system, to usefully employ the effects produced by the simultaneous production of pressurized steam and strengthened absorbent. Accordingly, these effects are advantageously employed in the combined operations of a steam-jet refrigeration means and a primary source of absorbent fluid (NaCl) in a closed circuit between the source and the absorber section of the absorber-freezer means; and a secondary heat transfer fluid (NaCl) flows in a closed circuit between the steam-jet refrigeration means and the input of dilute feed solution into the freezer section of the absorber-freezer means. A feature is the complementary refrigeration of heat transfer fluid (NaCl) by the steam-jet refrigeration means and by the absorber section of the absorber-freezer means, pumped through parallel closed circuits and passed through a pre-cooler means that lowers the temperature of the dilute feed solution near to freezing. Accordingly, the dilute feed solution is in optimum condition for processing in the freezer section of said absorber-freezer means.
A fourth utilitarian processing system advantageously combined with the hybrid power system disclosed herein is the Combined Cycle Gas Turbine Dual Chiller and Ice Thermal Storage System shown in FIG. 6 of the drawings. It is significant that this power system is adapted to be used with any one or all of the aforementioned processing systems as disclosed in FIGS. 3, 4 and 5. Accordingly, it will be observed that hot liquid working fluid is available for either or both steam generation or jet processes as shown in FIGS. 4 and 5, and also that super-heated steam is available for the chiller process as shown in FIG. 3. Each of these processes cooperate with the hybrid power system with remaining power used for co-generation of electrical power.